Channel selection in a shared spectrum communication network

ABSTRACT

A method for selecting at least one channel for a network element in a shared spectrum communication system is provided. The method includes identifying a plurality of candidate channels of a frequency band of the shared spectrum communication system. For each channel of the plurality of channels, the method further includes: evaluating the channel based on one or more of a plurality of criteria for the network element; scoring the channel based on the evaluation of the channel for the network element; and ranking the plurality of candidate channels based on the assigned scores for each of the plurality of channels. The method further includes selecting at least one channel based on the ranking of the plurality of candidate channels

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. Patent Application claims priority to, and the benefit of,U.S. Provisional Patent Application No. 62/731,408, titled “CHANNELSELECTION IN A SHARED SPECTRUM COMMUNICATION NETWORK” and filed on Sep.14, 2018, which is hereby incorporated by reference in its entirety.

BACKGROUND

The Citizens Broadband Radio System (CBRS) is a model for sharedspectrum use in the 3.5 GHz band as created by the FederalCommunications Commission of the United States government. The CBRSmodel includes three levels of access. Tier I of the CBRS model isdedicated to incumbents who currently use portions of the band. Tier IIof the CBRS model is allocated for Priority Access Licenses (so-calledPALs) which allow new or existing users to purchase a block of spectrumfor exclusive use in a geographic area provided there is no interferencewith Tier I users. Finally, Tier III of the CBRS model is allocated forGeneral Authorized Access (GAA) available to any use provided there isno interference to Tier I or Tier II users. Access across all tiers ismanaged by a Spectrum Access System (SAS).

The CBRS band includes 150 MHz of total bandwidth and depending onavailability, users may consume from 5 MHz up to the entire 150 MHz fora given geographic area. For convenience, the CBRS band can be thoughtof as channels. The 150 MHz can be represented as thirty 5 MHz channels,fifteen 10 MHz channels, seven 20 MHz channels or any appropriatecombination of 5, 10 and 20 MHz channels. For pedagogical purposes, thisdisclosure refers to a generic “channel”, independent of bandwidthunless otherwise noted.

Not all channels in the CBRS band are created equal. Some CBRS channelsmay be more sensitive, creating interference to, or receivinginterference from, users in adjacent bands. Some CBRS channels may besusceptible to a brief use suspension by the SAS due to temporalincumbent activity. Still others CRBS channels may have a higherprobability of limited access due to incumbent interference caused by anaggregation of user signals. Some CBRS channels, for sites located in anExclusion Zone, are prohibited for use all together.

For a wireless operator wishing to utilize the CBRS band, it is desiredto choose channels that would provide the best desired signal coverage,and be less susceptible to suspension or power reductions by the SAS,both at site commissioning and for future use. Common methods for asystem operator to choose a channel would be for a Citizens BroadbandRadio System Device (CBSD) to query the SAS for available channels andoptionally the maximum Effective Isotropic Radiated Power (EIRP) the SASwould allocate to the channel. The CBSD could choose the availablechannel that meets its EIRP needs. A second method would be for a CBSDto actively scan the radio frequencies associated with channels andmeasure the received channel power as an indication of channelutilization. The CBSD could choose the channel with the lowest receivedchannel power assuming this measurement indicates a lack of use byothers. Both methods may give a good indication of currently availablechannels but may turn out to be a poor channel selection due to factorsother than current availability.

This invention describes a more robust method for choosing a CBRSchannel attempting to maximize near and long term objectives.

SUMMARY

In one embodiment, the present invention provides a method for selectingat least one channel for a network element in a shared spectrumcommunication system. The method includes identifying a plurality ofcandidate channels of a frequency band of the shared spectrumcommunication system. For each channel of the plurality of channels, themethod further includes: evaluating the channel based on one or more ofa plurality of criteria for the network element; scoring the channelbased on the evaluation of the channel for the network element; andranking the plurality of candidate channels based on the assigned scoresfor each of the plurality of channels. The method further includesselecting at least one channel based on the ranking of the plurality ofcandidate channels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of one embodiment of a shared spectrumcommunication system that includes a channel evaluator according to theteachings of the present invention.

FIG. 2 is a flow chart of one embodiment of a process for selecting achannel for a network element in a shared spectrum communication systemaccording to the teachings of the present invention.

FIG. 3 is flow chart of another embodiment of a process for selecting achannel for a network element in a shared spectrum communication systemaccording to the teachings of the present invention.

FIG. 4 is a block diagram of another embodiment of a shared spectrumcommunication system that includes a channel evaluator according to theteachings of the present invention.

FIG. 5 is a flow chart of one embodiment of a process for evaluatingchannels for a network element in a shared spectrum communication systemaccording to the teachings of the present invention.

FIG. 6 is a block diagram of another embodiment of a shared spectrumcommunication system that includes a channel evaluator according to theteachings of the present invention.

FIG. 7 is a block diagram of one embodiment of a channel evaluator thatevaluates candidate channels for use by a network element in a sharedspectrum communication system according to the teachings of the presentinvention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of specific illustrative embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that other embodiments may be utilized and that logical,mechanical and electrical changes may be made without departing from thescope of the present invention. The following detailed description is,therefore, not to be taken in a limiting sense.

Embodiments of the present invention relate to selection of a channel ina frequency band of a shared spectrum communication system, such as theCitizens Broadband Radio System (CBRS) authorized by the FederalCommunications Commission. Embodiments of the present inventionrepresent an improvement to such shared spectrum communication systemsthrough consideration of various criteria used to rank the channels thatcan be requested by a network element such as a Citizens Broadband RadioSystem Device (CBSD). The ranking of channels is accomplished by a“channel evaluator” that may reside within a CBSD (FIG. 1), the spectrumaccess system (SAS) (FIG. 4) or as a stand-alone entity thatcommunicates with either a CBSD or the SAS of the CBRS. In eachembodiment, the channel evaluator identifies a number of candidatechannels that could be used by a network element. The Channel evaluatorthen uses one or more of a plurality of criteria to evaluate each of thecandidate channels to determine the relative merits of each of thecandidate channels as discussed in more detail below.

FIG. 1 is a block diagram of one embodiment of a shared spectrumcommunication system, indicated general at 100, which includes a channelevaluator 102 according to the teachings of the present invention. Inone embodiment, system 100 is a CBRS network. System 100 includes aspectrum access system (SAS) 104 and a number of network elements orCBSDs 106-1 to 106-N. In this embodiment, channel evaluator 102 residesin each CBSD and is used by the CBSD to evaluate and rank candidatechannels when the CBSD requests access to a channel from SAS 104.

SAS 104 grants access to a communication channel in system 100 for aCBSD using a known protocol established by, for example the WlnnForumstandard, which involves a request for access to a channel from theCBSD. However, the WlnnForum standard does not specify how the CBSDdetermines which channel to request. Thus, incorporation of channelevaluator 102 into the operation of system 100 is an improvement to theway that access is granted to channels in shared spectrum communicationsystems.

One embodiment of a process for selecting a channel for a networkelement (CBSD) in the shared spectrum communication system of FIG. 1 isillustrated in the flow chart of FIG. 2. When a CBSD, e.g., CBSD 106-1,is ready to request access to a channel, CBSD 106-1 requests a list ofchannels from channel evaluator 102 at block 202. Channel evaluator 102applies a number of criteria to evaluate a number of candidate channelsas explained in more detail below. At block 204, channel evaluator 102returns a list of channels to CBSD 106-1. The list of channels providedby channel evaluator 102 includes a ranking of the respective candidatechannels according the criteria used to evaluate the channels. At block206, the CBSD 106-1 selects one or more channels (such as a primarychannel and one or more secondary or backup channels) from the list ofchannels received from the channel evaluator. At block 208, the CBSD106-1 sends a request to SAS 104 to request access to the selectedchannels from the ranked list of channels. Thus, by evaluating thecandidate channels according to a set of criteria for the CBSD, thechannel assigned by the SAS is more likely to provide a better level ofservice than if a channel were selected without input from the channelevaluator. This is thus an improvement in shared spectrum communicationssystems.

FIG. 3 is flow chart of another embodiment of a process for selecting achannel for a network element in a shared spectrum communication system,such as system 100 of FIG. 1, according to the teachings of the presentinvention. The process begins as block 302 by identifying one or morecandidate channels. For example, in a CBRS, the process identifies oneor more of the channels in the 150 MHz channel in the 3.5 GHz band. Forexample, the process can identify any of the channels in the band, suchas any number of 5 MHz, 10 MHz, or 20 MHz channels. At blocks 304 and306, the process evaluates and scores each of the selected channelsuntil, at block 308, the process determines that there are no morechannels to evaluate and score.

The process evaluates the candidate channels based on a specified set ofcriteria. These criteria are provided, for example, by the networkelement or CBSD that is requesting the evaluation of the channels. Thefollowing is a non-exhaustive list of criteria that may be used toevaluate and score the candidate channels. Not all of the criteria areused in each instance. Further, other criteria can be used that assistthe CBSD in selecting a channel that improves the use of the sharedspectrum of the communication system. In one embodiment, the evaluationcriteria include:

DPA—Dynamic Protection Areas are frequency specific geographic regionsfor which a limited frequency band must suspend service if a federalincumbent wishes to temporarily use one or more channels in a geographicarea. In one embodiment, channels which are evaluated to begeographically distant or outside of the frequency range impacting theDPA are assigned a high channel score under this criteria. Similarly,channels for sites which are evaluated to be located close to the DPAand impacting the frequency range of the DPA are assigned a low scoreunder this criteria.

PAL—Priority Access Licenses are Tier II users of a CBRS that pay a feefor licensed access to a frequency band. PAL channels actively in useare not available to other PAL or GAA users and are not considered atblock 302 as available channels for evaluation or ranking (excluded fromstep 1). PAL channels that have been granted a license but not yet inuse are identified as candidate channels at block 302. PALs may bepurchased for a set geographic region (such as census tracts orcounties). Actual use of the PAL frequencies may be over a smallerregion which may grow over time. In one embodiment, channels which areevaluated to fall under a PAL license within a license area but not(yet) used activated or claimed as a PAL Protection Area (PPA) areassigned a low score under this criteria. This is due to the higherprobability of the channel becoming unavailable in the future due to PALexpansion. Similarly, channels which are evaluated to not be near afrequency overlapping PAL license area are assigned a high score underthis criteria.

Interference margin—Rules for the protection of some incumbents arebased on the aggregate interference of all sites using the same channelin geographic proximity to the incumbent. An example of this are FixedSatellite Station incumbents. Channel usage may be unrestricted untilthe population of neighbor CBRS sites builds to the point when incumbentaggregate interference thresholds are exceeded. The difference betweenthe total aggregate site interference signal level and the allowablethreshold is referred to as the interference margin. Sites with a lowerinterference margin have a higher probability of having their transmitpower reduced in the future due to future incumbent impact. Thus, in oneembodiment, channels for sites that are evaluated to have a lowinterference margin are assigned a low score and sites that areevaluated to have a high interference margin are assigned a high score.

In some embodiments, the score for interference margin accounts for thedifference between the individual interference for a channel and a fairquota. The fair quota is 1/N for N number of CBSD impacting anyprotection point. If the difference (Interference for a channel —1/Nfair quota) is positive, then the score for that channel will beproportionally low. Conversely, if the difference is negative, the scorefor the requested channel will be proportionally high.

Historical data—In one embodiment, temporal incumbent use history isused to develop pattern data. For example, offshore DPA use is dictatedby US navy radar operations. Naval operations may follow set shippingroutes, repeatable use regions and channel frequencies which cause someDPAs to be activated at a higher rate than others. In one embodiment,channels that are evaluated to be located near DPAs which have a higherhistorical activation rate receive a lower score than channels which seelower historical activation rates.

Coverage Area—In one embodiment, the potential coverage area of the CBSDis evaluated as a criteria in channel ranking. For example, channelsthat are found to be for sites that are located indoors, have a verysmall coverage area or located in isolated areas (such as large shippingterminals) receive a higher score than channels for sites that areoutdoors, have large coverage areas, or in congested areas. Thisreflects the lower probability of interference or incumbent overlap inisolated coverage areas.

Adjacent band—In one embodiment, the location of a channel within theband is evaluated as a criteria in ranking candidate channels. Forexample, channels located on the CBRS band edges (such as lower andupper edges) are more likely to cause interference to adjacent bands orbe subjected to interference from users in adjacent bands. Therefore, inone embodiment, channels that are evaluated to be edge channels receivea lower score than those located more central in frequency to the CBRSband.

Contiguous bandwidth—In one embodiment, the bandwidth of a channel isevaluated as a criteria in ranking candidate channels. Higher bandwidthchannels may be more susceptible to incumbent use or interference justbecause of the fact that their bandwidth occupies a larger frequencyrange. Therefore, candidate channels that are evaluated to have higherchannel bandwidths (e.g. 20 MHz) are assigned a lower score than lowerchannel bandwidths (e.g. 5 MHz).

For each criteria, scoring may utilize a coarse or fine granularity.Different score values may be used for different categories or criteria.For example, a binary “low” or “high” score may be applicable for theadjacent band evaluation. A qualitative score, such as “low,” “medium,”or “high,” may be more applicable to the contiguous bandwidth categoryor criteria. Furthermore, a numerical score, such as a value from 1 to10, may be more appropriate for DPA evaluation, with the extragranularity reflecting the distance and/or impact to a DPA region. Allscales are such that they can be optionally combined to form a finalscore for each channel at a given geographical location. In oneembodiment, the final score is used for channel ranking. Alternatively,in other embodiments, scores for the individual criteria are weightedbased on the CBSD use case and the overall score is a weightedcombination of the individual scores. In other embodiments, the overallscore is based on the score of one or more of the highest prioritycategories or criteria. In other embodiments, the final score can alsobe based on the priority of the CBSD based on different criteria. TheCBSD, in one embodiment, provides the priorities to the channelevaluator.

Returning to FIG. 3, the process ranks the channels at block 310 andthen the CBSD selects one or more channels (primary and secondary/backupchannels) to request from SAS 104 at block 312.

In one embodiment, the channel evaluation could be performed duringpre-deployment analysis and programmed into the CBSD before or duringdeployment. In other embodiments, the analysis is performed nearreal-time when the CBSD needs to request access to a channel. The CBSDwould then use this ranking to request primary and optionally,secondary/backup channels.

FIG. 4 is a block diagram of another embodiment of a shared spectrumcommunication system, indicated generally at 400, which includes achannel evaluator 402 disposed in SAS 404 according to the teachings ofthe present invention. In this embodiment, channel evaluator 402 pusheschannel rankings to each CBSD based on criteria for the specific CBSD.Each CBSD 406-1 to 406-N then uses the channel rankings to select andrequest one or more channels (such as primary and secondary/backupchannels) from SAS 404 similarly as explained above.

FIG. 5 is a flow chart of one embodiment of a process for evaluatingchannels for a network element in a shared spectrum communication systemaccording to the teachings of the present invention. The process of FIG.5 is the process that is used by the channel evaluator in each of FIGS.1, 4, and 6. The process of FIG. 5 differs from the process of FIG. 3 inthat, at block 512, the process stores the results of the evaluation andscoring of the candidate channels. This data is then available for theCBSDs to request when a channel assignment is needed. Since thisembodiment is not tied to a specific CBSD or a specific location, thechannel results are stored in relation to a spatial dimension. In allother respects, the process of FIG. 5 is as described above with respectto FIG. 3.

FIG. 6 is a block diagram of another embodiment of a shared spectrumcommunication system, indicated at 600, which includes a channelevaluator 602 that is a stand-alone entity and is not disposed in SAS604 or CBSDs 606-1 to 606-N. In this embodiment, channel evaluator 602communicates directly with CBSDs 606-1 to 606-N or indirectly throughSAS 604. Either way, channel evaluator pushes channel information toeach CBSD based on criteria for the specific CBSD. In some embodiments,the channel evaluator 602 pushes channel rankings to the CBSDs 606-1 to606-N. Each CBSD 606-1 to 606-N then uses the channel rankings to selectand request one or more channels (such as primary and secondary/backupchannels) from SAS 604 similarly as explained above. In otherembodiments, channel evaluator 602 ranks and also selects the channelfor the CBSD. In these embodiments, channel evaluator 602 just pushesthe selected channel to the CBSD.

FIG. 7 is a block diagram of one embodiment of a channel evaluator 700that evaluates candidate channels for use by a network element in ashared spectrum communication system according to the teachings of thepresent invention. Channel evaluator 700 includes a processor 702 thatis operable to read and execute instructions to perform the channelevaluation. In one embodiment, the instructions are stored (or otherwiseembodied) on or in an appropriate non-transitory storage medium or media704 (such as flash memory or other non-volatile memory, magnetic discdrives and/or optical disc drives) as channel evaluation function 706.Channel evaluator 700 includes memory 705 for storing the programinstructions of channel evaluation function 706 (and any related data)during execution by the processor 702. Memory 705 comprises, in oneimplementation, any suitable form of random access memory (RAM) nowknown or later developed, such as dynamic random access memory (DRAM).In other embodiments, other types of memory are used. Functionalitydescribed here as being implemented in software (channel evaluationfunction 706) can be implemented in other ways (for example, using anapplication specific integrated circuit (ASIC) or field programmablegate array (FPGA)). When run by processor 702, channel evaluationfunction 706 evaluates candidate channels using, for example, theprocess described above with respect to FIG. 5. In that process, channelevaluation function 706 uses data, as needed for the various criteria.In some embodiments, that data may be stored in databases 708 stored onstorage media 704 or may be retrieved from another entity such as SAS104 of FIG. 1 over communication interface 710.

The methods and techniques described here may be implemented in digitalelectronic circuitry, or with a programmable processor (for example, aspecial-purpose processor or a general-purpose processor such as acomputer) firmware, software, or in combinations of them. Apparatusembodying these techniques may include appropriate input and outputdevices, a programmable processor, and a storage medium tangiblyembodying program instructions for execution by the programmableprocessor. A process embodying these techniques may be performed by aprogrammable processor executing a program of instructions to performdesired functions by operating on input data and generating appropriateoutput. The techniques may advantageously be implemented in one or moreprograms that are executable on a programmable system including at leastone programmable processor coupled to receive data and instructionsfrom, and to transmit data and instructions to, a data storage system,at least one input device, and at least one output device. Generally, aprocessor will receive instructions and data from a read-only memoryand/or a random access memory. Storage devices suitable for tangiblyembodying computer program instructions and data include all forms ofnon-volatile memory, including by way of example semiconductor memorydevices, such as EPROM, EEPROM, and flash memory devices; magnetic diskssuch as internal hard disks and removable disks; magneto-optical disks;and DVD disks. Any of the foregoing may be supplemented by, orincorporated in, specially-designed application-specific integratedcircuits (ASICs) or Field Programmable Gate Arrays (FGPAs).

EXAMPLE EMBODIMENTS

Example 1 includes a method for selecting at least one channel for anetwork element in a shared spectrum communication system, the methodcomprising: identifying a plurality of candidate channels of a frequencyband of the shared spectrum communication system; for each channel ofthe plurality of channels: evaluating the channel based on one or moreof a plurality of criteria for the network element; scoring the channelbased on the evaluation of the channel for the network element; andranking the plurality of candidate channels based on the assigned scoresfor each of the plurality of channels; and selecting at least onechannel based on the ranking of the plurality of candidate channels.

Example 2 includes the method of example 1, wherein evaluating thechannel comprises evaluating the channel based on one or more of theplurality of criteria including: proximity to a dynamic protection area,existence of priority access license (PAL) that has not been activatedor claimed as a PAL Protection Area (PPA), interference margin,historical use by an incumbent user, coverage area, location of thechannel in the frequency band, and bandwidth of the channel.

Example 3 includes the method of any of examples 1 or 2, wherein scoringa channel comprises scoring the channel based on a weighted combinationof the evaluations of the one or more of the plurality of criteria.

Example 4 includes the method of any of examples 1 through 3, whereinscoring a channel comprises combining the results of the evaluation ofthe one or more of the plurality of criteria.

Example 5 includes the method of any of examples 1 through 4, whereinscoring the channel comprises, for each of the one or more of theplurality of criteria, assigning a score that is one of a numeric score,a qualitative score or a binary score

Example 6 includes the method of any of examples 1 through 5, whereinevaluating the channel comprises obtaining data from a source externalto the network element.

Example 7 includes the method of example 6, wherein obtaining datacomprises obtaining data from a spectrum access system (SAS).

Example 8 includes the method of any of examples 1 through 7, andfurther comprising requesting access to the selected at least onechannel of the plurality of candidate channels.

Example 9 includes a method for ranking channels for a network elementof a shared spectrum communication system, the method comprising:identifying a plurality of candidate channels of a frequency band of theshared spectrum communication system; for each channel of the pluralityof channels: evaluating the channel based on one or more of a pluralityof criteria for the network element; scoring the channel based on theevaluation of the channel for the network element; ranking the pluralityof candidate channels for the network element based on the assignedscores for each of the plurality of candidate channels; and storing theranking of the plurality of candidate channels for the network elementto use in selecting a channel for wireless communication.

Example 10 includes the method of example 9, wherein evaluating thechannel comprises evaluating the channel based on one or more of theplurality of criteria including: proximity to a dynamic protection area,existence of priority access license (PAL) that has not been activatedor claimed as a PAL Protection Area (PPA), interference margin,historical use by an incumbent user, coverage area, location of thechannel in the frequency band, and bandwidth of the channel.

Example 11 includes the method of any of examples 9 or 10, whereinscoring a channel comprises scoring the channel based on a weightedcombination of the evaluations of the one or more of the plurality ofcriteria.

Example 12 includes the method of any of examples 9 through 11, whereinscoring a channel comprises combining the results of the evaluation ofthe one or more of the plurality of criteria.

Example 13 includes the method of any of examples 9 through 12, whereinscoring the channel comprises, for each of the one or more of theplurality of criteria, assigning a score that is one of a numeric score,a qualitative score or a binary score.

Example 14 includes the method of any of examples 9 through 13, whereinevaluating the channel comprises obtaining data from a source externalto the network element.

Example 15 includes the method of example 14, wherein obtaining datacomprises obtaining data from a spectrum access system (SAS).

Example 16 includes the method of any of examples 9 through 15, andfurther comprising sharing the channel rankings with the networkelement.

Example 17 includes a method for selecting a channel for a networkelement in a shared spectrum communication system, the methodcomprising: requesting a list of channels from a channel evaluator bythe network element; receiving the list of channels, wherein the list ofchannels is ranked according to a score based on one or more criteriafor the network element; selecting, by the network element, one or moreof the channels from the list of channels; and requesting access to theselected one or more channels from a spectrum access system.

Example 18 includes the method of example 17, wherein requesting a listof channels from the channel evaluator comprises requesting a list ofchannels from the channel evaluator that is one of: part of the spectrumaccess system, part of the network element, or a separate entity.

Example 19 includes the method of any of examples 17 and 18, whereinrequesting a list of channels further includes specifying the criteriato be used in scoring a set of candidate channels.

Example 20 includes the method of example 19, wherein specifying thecriteria further comprises specifying relative weights to be given toeach of the specified criteria.

Example 21 includes the method of any of examples 19 or 20, whereinspecifying the criteria comprises specifying one or more of: proximityto a dynamic protection area, existence of priority access license (PAL)that has not been activated or claimed as a PAL Protection Area (PPA),interference margin, historical use by an incumbent user, coverage area,location of the channel in the frequency band, and bandwidth of thechannel.

Example 22 includes a channel evaluator, comprising: a processor; acommunication interface; a storage media, the storage media storing achannel evaluation function; and wherein the processor is configured toexecute the channel evaluation function to evaluate channels for anetwork element of a shared spectrum communication system by:identifying a plurality of candidate channels of a frequency band of theshared spectrum communication system; for each channel of the pluralityof channels: evaluating the channel based on one or more of a pluralityof criteria for the network element; scoring the channel based on theevaluation of the channel for the network element; ranking the pluralityof candidate channels for the network element based on the assignedscores for each of the plurality of candidate channels; and storing theranking of the plurality of candidate channels for the network elementto use in selecting a channel for wireless communication.

Example 23 includes the channel evaluator of example 22, wherein thechannel evaluator is located in one of (1) the network element, (2) aspectrum access system, and (3) a stand-alone entity.

Example 24 includes the channel evaluator of any of examples 22 and 23,and further comprising a database that stores the plurality of criteriaused by the channel evaluation function.

Example 25 includes the channel evaluator of any of examples 22-24, andfurther including a communication interface that is configured to enablecommunication with another entity to retrieve the plurality of criteriaused by the channel evaluation function.

Example 26 includes the channel evaluator of any of examples 22-25,wherein evaluating the channel comprises evaluating the channel based onone or more of the plurality of criteria including: proximity to adynamic protection area, existence of priority access license (PAL) thathas not been activated or claimed as a PAL Protection Area (PPA),interference margin, historical use by an incumbent user, coverage area,location of the channel in the frequency band, and bandwidth of thechannel.

Example 27 includes the channel evaluator of any of examples 22-26,wherein scoring a channel comprises scoring the channel based on aweighted combination of the evaluations of the one or more of theplurality of criteria.

Example 28 includes the channel evaluator of any of examples 22-27,wherein scoring a channel comprises combining the results of theevaluation of the one or more of the plurality of criteria.

Example 29 includes the channel evaluator of any of examples 22-28,wherein scoring the channel comprises, for each of the one or more ofthe plurality of criteria, assigning a score that is one of a numericscore, a qualitative score or a binary score.

Example 30 includes a non-transitory computer readable medium storing aprogram causing a computer to perform a method to evaluate a pluralityof candidate channels for a network element in a shared spectrumcommunication system, the method comprising: identifying a plurality ofcandidate channels of a frequency band of the shared spectrumcommunication system; for each channel of the plurality of channels:evaluating the channel based on one or more of a plurality of criteriafor the network element; scoring the channel based on the evaluation ofthe channel for the network element; ranking the plurality of candidatechannels for the network element based on the assigned scores for eachof the plurality of candidate channels; and storing the ranking of theplurality of candidate channels for the network element to use inselecting a channel for wireless communication.

Example 31 includes the non-transitory computer readable media ofexample 30, wherein evaluating the channel comprises evaluating thechannel based on one or more of the plurality of criteria including:proximity to a dynamic protection area, existence of priority accesslicense (PAL) that has not been activated or claimed as a PAL ProtectionArea (PPA), interference margin, historical use by an incumbent user,coverage area, location of the channel in the frequency band, andbandwidth of the channel.

Example 32 includes the non-transitory computer readable media of any ofexamples 30-31, wherein scoring a channel comprises scoring the channelbased on a weighted combination of the evaluations of the one or more ofthe plurality of criteria.

Example 33 includes the non-transitory computer readable media of any ofexamples 30-32, wherein scoring a channel comprises combining theresults of the evaluation of the one or more of the plurality ofcriteria.

Example 34 include the non-transitory computer readable media of any ofexamples 30-33, wherein scoring the channel comprises, for each of theone or more of the plurality of criteria, assigning a score that is oneof a numeric score, a qualitative score or a binary score.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

1. A method for selecting at least one channel for a network element in a shared spectrum communication system, the method comprising: identifying a plurality of candidate channels of a frequency band of the shared spectrum communication system; for each channel of the plurality of channels: evaluating the channel based on one or more of a plurality of criteria for the network element, wherein each of the plurality of criteria are defined by at least one aspect of the shared spectrum communication system; scoring the channel based on the evaluation of the channel for the network element; and ranking the plurality of candidate channels based on the assigned scores for each of the plurality of channels; and selecting at least one channel based on the ranking of the plurality of candidate channels.
 2. The method of claim 1, wherein evaluating the channel comprises evaluating the channel based on one or more of the plurality of criteria including: proximity to a dynamic protection area, existence of priority access license (PAL) that has not been activated or claimed as a PAL Protection Area (PPA), interference margin, interference margin accounting for a difference between an individual interference for a channel and a fair quota, historical use by an incumbent user, coverage area, location of the channel in the frequency band, and bandwidth of the channel.
 3. The method of claim 1, wherein scoring a channel comprises scoring the channel based on a weighted combination of the evaluations of the one or more of the plurality of criteria.
 4. The method of claim 1, wherein scoring a channel comprises combining the results of the evaluation of the one or more of the plurality of criteria.
 5. The method of claim 1, wherein scoring the channel comprises, for each of the one or more of the plurality of criteria, assigning a score that is one of a numeric score, a qualitative score or a binary score.
 6. The method of claim 1, wherein evaluating the channel comprises obtaining data from a source external to the network element.
 7. The method of claim 6, wherein obtaining data comprises obtaining data from a spectrum access system (SAS).
 8. The method of claim 1, and further comprising requesting access to the selected at least one channel of the plurality of candidate channels.
 9. A method for ranking channels for a network element of a shared spectrum communication system, the method comprising: identifying a plurality of candidate channels of a frequency band of the shared spectrum communication system; for each channel of the plurality of channels: evaluating the channel based on one or more of a plurality of criteria for the network element, wherein each of the plurality of criteria are defined by at least one aspect of the shared spectrum communication system; scoring the channel based on the evaluation of the channel for the network element; ranking the plurality of candidate channels for the network element based on the assigned scores for each of the plurality of candidate channels; and storing the ranking of the plurality of candidate channels for the network element to use in selecting a channel for wireless communication.
 10. The method of claim 9, wherein evaluating the channel comprises evaluating the channel based on one or more of the plurality of criteria including: proximity to a dynamic protection area, existence of priority access license (PAL) that has not been activated or claimed as a PAL Protection Area (PPA), interference margin, interference margin accounting for a difference between an individual interference for a channel and a fair quota, historical use by an incumbent user, coverage area, location of the channel in the frequency band, and bandwidth of the channel.
 11. The method of claim 9, wherein scoring a channel comprises scoring the channel based on a weighted combination of the evaluations of the one or more of the plurality of criteria.
 12. The method of claim 9, wherein scoring a channel comprises combining the results of the evaluation of the one or more of the plurality of criteria.
 13. The method of claim 9, wherein scoring the channel comprises, for each of the one or more of the plurality of criteria, assigning a score that is one of a numeric score, a qualitative score or a binary score.
 14. The method of claim 9, wherein evaluating the channel comprises obtaining data from a source external to the network element.
 15. The method of claim 14, wherein obtaining data comprises obtaining data from a spectrum access system (SAS).
 16. The method of claim 9, and further comprising sharing the channel rankings with the network element.
 17. A method for selecting a channel for a network element in a shared spectrum communication system, the method comprising: requesting a list of channels from a channel evaluator by the network element; receiving the list of channels, wherein the list of channels is ranked according to a score based on one or more criteria for the network element, wherein each of the plurality of criteria are defined by at least one aspect of the shared spectrum communication system; selecting, by the network element, one or more of the channels from the list of channels; and requesting access to the selected one or more channels from a spectrum access system.
 18. The method of claim 17, wherein requesting a list of channels from the channel evaluator comprises requesting a list of channels from the channel evaluator that is one of: part of the spectrum access system, part of the network element, or a separate entity.
 19. The method of claim 17, wherein requesting a list of channels further includes specifying the criteria to be used in scoring a set of candidate channels.
 20. The method of claim 19, wherein specifying the criteria further comprises specifying relative weights to be given to each of the specified criteria.
 21. The method of claim 19, wherein specifying the criteria comprises specifying one or more of: proximity to a dynamic protection area, existence of priority access license (PAL) that has not been activated or claimed as a PAL Protection Area (PPA), interference margin, interference margin accounting for a difference between an individual interference for a channel and a fair quota, historical use by an incumbent user, coverage area, location of the channel in the frequency band, and bandwidth of the channel.
 22. A channel evaluator, comprising: a processor; a communication interface; a storage media, the storage media storing a channel evaluation function; and wherein the processor is configured to execute the channel evaluation function to evaluate channels for a network element of a shared spectrum communication system by: identifying a plurality of candidate channels of a frequency band of the shared spectrum communication system; for each channel of the plurality of channels: evaluating the channel based on one or more of a plurality of criteria for the network element, wherein each of the plurality of criteria are defined by at least one aspect of the shared spectrum communication system; scoring the channel based on the evaluation of the channel for the network element; ranking the plurality of candidate channels for the network element based on the assigned scores for each of the plurality of candidate channels; and storing the ranking of the plurality of candidate channels for the network element to use in selecting a channel for wireless communication.
 23. The channel evaluator of claim 22, wherein the channel evaluator is located in one of (1) the network element, (2) a spectrum access system, and (3) a stand-alone entity.
 24. The channel evaluator of claim 22, and further comprising a database that stores the plurality of criteria used by the channel evaluation function.
 25. The channel evaluator of claim 22, and further including a communication interface that is configured to enable communication with another entity to retrieve the plurality of criteria used by the channel evaluation function.
 26. The channel evaluator of claim 22, wherein evaluating the channel comprises evaluating the channel based on one or more of the plurality of criteria including: proximity to a dynamic protection area, existence of priority access license (PAL) that has not been activated or claimed as a PAL Protection Area (PPA), interference margin, interference margin accounting for a difference between an individual interference for a channel and a fair quota, historical use by an incumbent user, coverage area, location of the channel in the frequency band, and bandwidth of the channel.
 27. The channel evaluator of claim 22, wherein scoring a channel comprises scoring the channel based on a weighted combination of the evaluations of the one or more of the plurality of criteria.
 28. The channel evaluator of claim 22, wherein scoring a channel comprises combining the results of the evaluation of the one or more of the plurality of criteria.
 29. The channel evaluator of claim 22, wherein scoring the channel comprises, for each of the one or more of the plurality of criteria, assigning a score that is one of a numeric score, a qualitative score or a binary score.
 30. A non-transitory computer readable medium storing a program causing a computer to perform a method to evaluate a plurality of candidate channels for a network element in a shared spectrum communication system, the method comprising: identifying a plurality of candidate channels of a frequency band of the shared spectrum communication system; for each channel of the plurality of channels: evaluating the channel based on one or more of a plurality of criteria for the network element, wherein each of the plurality of criteria are defined by at least one aspect of the shared spectrum communication system; scoring the channel based on the evaluation of the channel for the network element; ranking the plurality of candidate channels for the network element based on the assigned scores for each of the plurality of candidate channels; and storing the ranking of the plurality of candidate channels for the network element to use in selecting a channel for wireless communication.
 31. The non-transitory computer readable media of claim 30, wherein evaluating the channel comprises evaluating the channel based on one or more of the plurality of criteria including: proximity to a dynamic protection area, existence of priority access license (PAL) that has not been activated or claimed as a PAL Protection Area (PPA), interference margin, interference margin accounting for a difference between an individual interference for a channel and a fair quota, historical use by an incumbent user, coverage area, location of the channel in the frequency band, and bandwidth of the channel.
 32. The non-transitory computer readable media of claim 30, wherein scoring a channel comprises scoring the channel based on a weighted combination of the evaluations of the one or more of the plurality of criteria.
 33. The non-transitory computer readable media of claim 30, wherein scoring a channel comprises combining the results of the evaluation of the one or more of the plurality of criteria.
 34. The non-transitory computer readable media of claim 30, wherein scoring the channel comprises, for each of the one or more of the plurality of criteria, assigning a score that is one of a numeric score, a qualitative score or a binary score. 